Langerhans cell hyperplasia and IgE expression in canine atopic dermatitis

Langerhans cells appear to be critical for IgE-mediated allergen capture and presentation in human atopic dermatitis. The present study sought to determine whether epidermal (i.e Langerhans cells) and dermal dendritic cells in the skin of dogs with atopic dermatitis are hyperplastic and expressed surface IgE. Frozen sections of lesional or nonlesional atopic and normal control canine skin were immunostained with CD1a-, CD1c-, and IgE-specific monoclonal antibodies. The enumeration of cells was performed by morphometry in both the epidermis and the dermis. Cell counts were compared with each individual’s total serum IgE levels. Higher numbers of epidermal and dermal dendritic cells were present in atopic dogs than in normal control animals. Epidermal Langerhans cell counts were significantly higher in lesional than in nonlesional atopic specimens. IgE⁺ dendritic cells were observed in lesional atopic epidermis and dermis, and nonlesional atopic dermis, but not in normal control skin specimens. The percentages of IgE⁺ dendritic cells were correlated with each patient’s total serum IgE levels. These results demonstrate dendritic cell hyperplasia and IgE expression in canine atopic dermatitis. Increased epidermal Langerhans cell counts in lesional specimens suggest an epidermal allergen contact in canine atopic dermatitis.     

Longwave ultraviolet radiation (UVA, 320-400 nm)-induced tan protects human skin against further UVA injury

The protective effect of a UVA (320-400 nm) induced tan against cutaneous injury by further UVA-irradiation was studied by evaluating the histopathologic changes in tanned and untanned normal human buttock skin 24 h after exposure to 2 and 4 minimal erythema doses of UVA. In each subject there were fewer polymorphonuclear leukocytes and less endothelial cell prominence and vessel wall necrosis in the UVA tanned skin than in the untanned UVA-irradiated skin. In the tanned control and tanned UVA-irradiated skin there was a prominent mononuclear cell inflammatory infiltrate that was much greater than in untanned skin. In immunoperoxidase stained tissue sections, the mononuclear cells were predominantly T cells, and in all of the specimens the number of phenotypic helper/inducer cells exceeded the phenotypic cytotoxic/suppressor cells. This demonstrates that a UVA tan provides photoprotection against acute UVA exposure. In addition, tanning, with or without further UVA-irradiation, was associated with a mononuclear cell inflammatory infiltrate.     

The distribution and quantification of the Langerhans cell in normal human epidermis

The distribution of the Langerhans cell in normal human skin was determined using the mouse monoclonal antibody NA1/34 in a standard immunoperoxidase technique. Langerhans cells were counted in 106 specimens of clinically and histologically normal skin which was obtained from 95 out-patients (97 specimens) and five cadavers (nine specimens). Langerhans cell density was evaluated both as the number of Langerhans cells overlying 200 basal cells and as the number of Langerhans cells per linear millimetre of surface epidermis. The mean values of Langerhans cell density at each site were as follows: trunk 25 per 200 basal cells/ 32 per linear mm; upper limb 29 per 200 basal cells/33 per linear mm; face and neck 31 per 200 basal cells 34 per linear mm; lower limb 28 per 200 basal cells/32 per linear mm; palm 10 per 200 basal cells/18 per linear mm and sole 11 per 200 basal cells/17 per linear mm.     

Immuno-electron microscopic studies of surface receptors and antigens of human Langerhans cells

A heteroantiserum, prepared in rabbits against fractionated cell membranes of a human B-lymphoblastoid cell line, was used to study the distribution of Ia antigen(s) in human epidermis. Indirect immunofluorescence staining demonstrated specific reactivity of dendritic supra-basal cells, consistent in location with Langerhans cells. Basally located cells were noted in biopsy specimens from vitiliginous skin and from the leukodermatous regions of halo naevi. The specificity of the reaction was confirmed at the ultrastructural level by means of ferritin labelling methods. Cell surface staining was confined in the epidermis to Langerhans cells. Fc and C3' receptors were studied by means of rosetting methods. Negative results were obtained on frozen sections, while 2-3% of cells formed rosettes when applied to an epidermal cell suspension.     

The poikiloderma of Rothmund-Thomson syndrome: changes in Langerhans cell morphology and distribution

A black girl with the Rothmund-Thomson syndrome is presented. Immunophenotyping of subpopulations of immunocompetent cells in a biopsy of an atrophic hyperpigmented skin lesion revealed sparsity and unusual distribution of epidermal Langerhans cells. These cells were mainly located in the basal layer of the epidermis and did not show the usual dendritic pattern. Impressive immunoreactivity of the dermal infiltrate was observed by anti-HLA-DR staining. The changes in Langerhans cell morphology and distribution may indicate functional impairment of the up-regulating arm of skin immunity.     

Tattooing increases the number of Langerhans cells in skin: an immunocytochemical study

Abstract Tattooing is an act of permanent marking of the skin with indelible patterns by pricking and inserting pigments. Langerhans cells (LCS) are dendritic cells normally present in suprabasal layers of the epidermis of the skin. To assess whether there were any effects caused by the tattooing on Langerhans cell population and cutaneous nerves, skin from affected areas (n=15) was compared with controls (n=10). Frozen sections were immunostained with antisera to S-100. No discernible change either in distribution or in number of Langerhans cells and nerves was seen upon comparison with control skin taken from different areas, but all of the specimens taken from affected areas had a significant increase in the number of Langerhans cells (p < 0.001) even after several years of tattooing with no change in the cutaneous nerves. Thus, the study shows persistent stimulation of Langerhans cell population in tattooed skin.     

CD1a、CD68在继发性瘢痕疙瘩中的表达及意义

目的 探讨继发性瘢痕疙瘩皮损中表皮朗格汉斯细胞（LC）和真皮CD68阳性组织细胞的分布和密度。方法 取30例继发性瘢痕疙瘩患者的皮损、14例正常人皮肤组织切片进行CD1a和CD68免疫组化染色。以测微尺标定目镜方格计数方格内阳性细胞数,计算出单位面积内细胞的密度。组间比较采用SPSS软件进行 Student t检验。结果 在继发性瘢痕疙瘩表皮内CD1a阳性LC密度为（61 ± 49）个/mm2,正常表皮为（258 ± 61）个/mm2,两组比较,t = 9.88,P ＜ 0.01;继发性瘢痕疙瘩真皮CD1a阳性细胞密度为（40 ± 65）个/mm2。继发性瘢痕疙瘩表皮中无CD68阳性细胞,真皮内CD68阳性组织细胞密度为（287 ± 73）/mm2,正常皮肤为（290 ± 22）个/mm2,两组比较,t = 0.02,P ＞ 0.05。继发性瘢痕疙瘩真皮浅层CD68阳性组织细胞占真皮中所有细胞的62% ± 12%,而正常皮肤为70% ± 14%,两组比较,t = 2.66,P ＜ 0.05。 结论 继发性瘢痕疙瘩表皮中LC减少,无CD68阳性的细胞。真皮中LC增多;真皮浅层CD68阳性组织细胞占真皮中所有细胞的比例下降。     

Immunohistochemical analysis of S100-positive epidermal Langerhans cells in dermatofibroma

Dermatofibroma is a dermal fibrohistiocytic neoplasm. The Langerhans cells are the immunocompetent cells of the epidermis, and they represent the first defense barrier of the immune system towards the environment. The objective was to immunohistologically compare the densities of S100-positive Langerhans cells in the healthy peritumoral epidermis against those in the epidermis overlying dermatofibroma (20 cases), using antibodies against the S100 molecule (the immunophenotypic hallmark of Langerhans cells). The control group (normal, healthy skin) included ten healthy age and sex-matched individuals who underwent skin biopsies for benign skin lesions. A significantly high density of Langerhans cells was observed both in the epidermis of the healthy skin (6.00 ± 0.29) and the peritumoral epidermis (6.44 ± 0.41) vs. those in the epidermis overlying the tumor (1.44 ± 0.33, p < 0.05). The quantitative deficit of Langerhans cells in the epidermis overlying dermatofibroma may be a possible factor in its development.     

An investigation of circulating and in situ lymphocyte subsets and Langerhans cells in the skin and cervix of patients with chronic renal failure

This study was designed to detect possible changes in the immunocytology of the human immune system in the skin, cervix and peripheral blood of patients with chronic renal failure (CRF) treated by conservative methods, haemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD). In the skin, Langerhans cell numbers were reduced in CRF, CAPD and HD patients but in the cervix, Langerhans cells were reduced only in the CRF patients. There was a preponderance of T suppressor lymphocytes compared with T helper lymphocytes in the epidermis in the CRF and the CAPD groups. The presence of natural killer cells in the epidermis of the renal groups compared to controls was significant in the CRF and HD patients while the presence of T suppressor lymphocytes in the epidermis compared to controls was significant only in the CAPD patients. In the dermis, there was a mixed cellular infiltrate of T helper and T suppressor lymphocytes but with no subset attaining significance. The dermal infiltrate of T helper lymphocytes in all three groups of renal patients was significantly reduced compared to controls. In CRF patients, peripheral blood pan T cells, T helper and T suppressor lymphocytes and B lymphocytes were reduced, while T suppressor lymphocytes were reduced in both HD and CAPD patients, compared to controls. Though the results confirm alteration of the immunocytology of the skin, cervix and peripheral blood, we could not relate them to a clinical finding.     

A quantitative analysis of the Langerhans cell in chronic plaque psoriasis

The mouse monoclonal antibody, NAI/34, in a standard immunoperoxidase technique, was used to count Langerhans cells in skin obtained from nine patients who were suffering from chronic plaque psoriasis. Biopsies were obtained from involved skin, clinically uninvolved skin and clinically healed skin following treatment with tar and/or dithranol. Langerhans cell numbers were expressed both as the absolute number of Langerhans cells per linear millimetre of surface epidermis and also as the number of Langerhans cells overlying 200 basal cells. An analysis of variance showed that in the active edge of a plaque of psoriasis, the absolute number of Langerhans cells was increased compared to adjacent uninvolved skin but when expressed as a ratio relative to the number of basal cells present, the number was decreased. This ratio returned to normal in healed skin. The ratio of Langerhans cells to basal cells in clinically uninvolved and in healed skin is the same ratio as we have found in over 100 specimens of normal skin obtained from non-psoriatic individuals.     

Langerhans cell density in epithelial skin tumors correlates with epithelial differentiation but not with the peritumoral infiltrate

We investigated the intraepithelial density of Langerhans cells in 17 epithelial skin tumors by immunohistologic and morphometric methods. There was a significant difference between seborrheic keratosis (Langerhans cell density 431 +/- 31/mm2; normal epidermis: 378 +/- 20/mm2), basal cell carcinoma (28 +/- 6/mm2), and squamous cell carcinoma (100 +/- 21/mm2). No correlation was found between the Langerhans cell density and the number of intraepithelial T lymphocytes or the extent of the peritumoral inflammatory infiltrate. A significant inverse correlation was demonstrated between mean nuclear area of the epithelial tissue and the Langerhans cell density (r = -0.7; p less than 0.05). These data indicate that the number of Langerhans cells does not influence the extent of the antitumoral immune response. The correlation with the level of epithelial differentiation may be due to different homing conditions.     

Tumour necrosis factor alpha is pro-inflammatory in normal human skin and modulates cutaneous adhesion molecule expression

Tumour necrosis factor a (TNF-α) is a potent immunoregulatory cytokine produced by many cutaneous cells, including kcratinocytes, mast cells and Langerhans cells. To explore its potential role in inflammatory skin disease, we have studied immunohistochemically the effects of intradermal recombinant human TNF-α (rHuTNF-α) on cutaneous inflammatory cells, adhesion molecules and Langerhans cells in normal human skin. Volunteers received rHuTNF-α 100U (group A), 5000 U (group B), or 100 U daily for 5 days (group C), and biopsies were taken at 6 h (groups A and B), or 6 h after the final injection (group C). An inflammatory cell infiltrate developed in all cases: following single injections of either 100 or 5000 U rHuTNF-α this was predominantly neutrophilic, whereas following multiple injections of 100 U few neutrophils were seen, although many lymphocytes (CD3⁺, CD4⁴) were present. In all groups there was an increase in cells of monocyte/macrophage lineage (CD36⁾⁺. TNF-α induced a dose- and time-dependent decrease in CDla⁺ epidermal Langerhans cell numbers and an increase in dermal CDla⁴ cells, suggesting migration of Langerhans cells away from the epidermis. TNF-α induced endothelial E-selectin, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in all groups, and adhesion molecule expression by interstitial dermal dendritic cells (ICAM-1 and VCAM-1) and keratinocytes (ICAM-1) was observed. These findings indicate that TNF-α is a potent modulator of cutaneous immune function in vivo, and this central role in the cutaneous immune response suggests that TNF-α may be an attractive target for therapeutic inhibition.     

Fc epsilon R11/CD23 receptor distribution in patch test reactions to aeroallergens in atopic dermatitis.

There is increasing evidence that exposure to organic allergens may induce or exacerbate lesional skin in patients with atopic dermatitis. In this study, patients with atopic dermatitis were patch tested to 11 common organic allergens and to control chambers containing 0.4% phenol and 50% glycerin in 0.9% saline. In biopsies from positive patch test reactions, patch test control skin, lesional eczematous and non-lesional skin from atopic individuals, and normal skin from non-atopic volunteers, the presence and distribution of macrophages (RFD7+), dendritic cells (RFD1+), and Langerhans cells, and the expression of the low-affinity receptor for IgE (CD23) were investigated. In patch test reactions and lesional skin samples, inflammatory infiltrates of diffusely distributed macrophages (RFD7+), dendritic cells (RFD1+), T lymphocytes (RFTmix+), and Langerhans cells (CD1+) were seen, the latter being present in both the epidermis and the dermis. The numbers of Langerhans cells were reduced in the epidermis and increased in the dermis in patch test reactions and lesional skin compared to their controls. Double staining revealed a change in the distribution of CD23 antigen. In patch test control and non-lesional biopsies many macrophages and only a few Langerhans cells within the dermal infiltrates expressed this antigen. In patch test reaction and lesional skin samples, however, the proportion of CD23+ dermal Langerhans cells had increased compared to macrophages. Furthermore, in these latter samples an increased proportion of dermal CD1+ cells expressed the dendritic cell (RFD1+) marker. These results show that following antigen challenge there are marked similarities between the phenotype of the cellular infiltrate in patch test reaction and lesional skin biopsies, and also demonstrate a changing distribution of CD23 on antigen-presenting cells.     

In situ identification of mononuclear cells in lichen planus

In this study, the in situ immunological typing of cell populations in lichen planus was attempted. T lymphocytes and suppressor/cytotoxic subsets, B lymphocytes, macrophages, immunocytes and Langerhans' cells were studied by one or more technical parameters and semiquantitative assessment of T cell populations were carried out. A critical evaluation of assays for T cell characterization was also attempted. T cells were found predominant in lichen planus infiltrate but macrophages were also many. Langerhans' cells were increased in the epidermis compared to normal skin and contact dermatitis.     

Thymopoietin-like substance in human skin

A heterologous antithymopoietin (anti-TP) antibody was used to determine whether a TP-like molecule is present in the epidermis, since such factors have been postulated to play a part in known T cell-epidermal cell interaction. Examination of cytocentrifuge smears of freshly separated human epidermal cells stained by indirect immunofluorescence revealed that 8-14% of these cells possessed cytoplasmic reactivity with the anti-TP antibody. Similarly, 2-5% of human epidermal cells, maintained in tissue culture for 2-8 weeks, showed cytoplasmic staining with the anti-TP antibody. Double-labeling immunofluorescence studies, with the anti-TP antibody and a monoclonal antibody specifically reactive with Langerhans cells (OKT6), demonstrated that cells possessing this TP-like substance were not Langerhans cells. In situ studies of 4-microns frozen sections of normal human skin indicated that the cell population which possesses the TP-like substance is the basal layer of keratincoytes in the epidermis.     

Human epidermal Langerhans cells express the tight junction protein claudin-1 and are present in human genetic claudin-1 deficiency (NISCH syndrome)

Abstract:  Claudin-1 (CLDN1) is a structural tight junction (TJ) protein and is expressed in differentiating keratinocytes and Langerhans cells in the epidermis. Our objective was to identify immunoreactive CLDN1 in human epidermal Langerhans cells and to examine the pattern of epidermal Langerhans cells in genetic human CLDN1 deficiency [neonatal ichthyosis, sclerosing cholangitis (NISCH) syndrome]. Epidermal cells from healthy human skin labelled with CLDN1-specific antibodies were analysed by confocal laser immunofluorescence microscopy and flow cytometry. Skin biopsy sections of two patients with NISCH syndrome were stained with an antibody to CD1a expressed on epidermal Langerhans cells. Epidermal Langerhans cells and a subpopulation of keratinocytes from healthy skin were positive for CLDN1. The gross number and distribution of epidermal Langerhans cells of two patients with molecularly confirmed NISCH syndrome, however, was not grossly altered. Therefore, CLDN1 is unlikely to play a critical role in migration of Langerhans cells (or their precursors) to the epidermis or their positioning within the epidermis. Our findings do not exclude a role of this TJ molecule once Langerhans cells have left the epidermis for draining lymph nodes.     

A Case of Chronic GVHD Following Bone Marrow Transplantation from a Phenotypically HLA-Matched Unrelated Donor

A 45-year-old male with chronic myelocytic leukemia who received a bone marrow transplantation from a phenotypically HLA-matched unrelated donor developed chronic GVHD on day 100 post transplantation. He developed a slight fever, malaise, hepatic dysfunction and extensive itchy erythema with scaling over his entire body. The inflammatory skin lesion developed into erythroderma in about two weeks. H&E staining of a skin biopsy revealed eosinophilic bodies and a lymphocytic infiltration in the dermis and epidermis, which were compatible with the early phases of chronic GVHD. Immunohistochemistry revealed that keratinocytes expressed dense HLA-DR and ICAM-1 epitopes. Langerhans cells (CD1a⁺ cells) had disappeared from the epidermis. Many T cells (CD3⁺ cells) had migrated into the epidermis as well as into the reticular dermis. The majority of the T cells in the epidermis were CD8⁺ cells, while almost all the T cells in the dermis were CD4⁺ cells. These immunohistochemical features were similar to those previously reported for acute cutaneous GVHD. Despite the corticosteroid therapy, the eruptions did not disappear. The patient was then treated with whole body bath-methoxsalen (Oxsoralen®) plus ultraviolet A (UVA). The bath-psoralen plus UVA therapy was effective in this patient.     

Langerhans cells and mycosis fungoides–a critical overview of their pathogenic role in the disease

Skin biopsies from seven patients with mycosis fungoides in various clinical stages (patches, plaques, nodules) were studied immunohistochemically and ultrastructurally, with the aim of investigating and quantifying the distribution of Langerhans cells and their relationships to mycosis cells. Our findings have revealed that in patches and plaques both Langerhans cells and mycosis cells were numerous in the epidermis. Notwithstanding this, in all the specimens examined, only one Langerhans cell forming close contact with a mycosis cell was detected. In the nodules, Langerhans cells and mycosis cells were sparse in the epidermis and no contacts were seen between them. Moreover, in all the patients studied, only a single Langerhans cell was found in the dermal infiltrate without any closely related mycosis cells. Conversely, numerous interdigitating cells have been found in the dermis of patches and plaques, often tightly adhering to mycosis cells. In the nodule, a few scattered interdigitating cells were seen, but often these had close contacts with neoplastic lymphoid cells. These findings indicate that close apposition between Langerhans cells and mycosis cells, which led previous authors to hypothesize a persistent stimulatory action of Langerhans cells on T lymphocytes, eventually leading to the malignant transformation of the latter, is unusual in mycosis fungoides. Therefore, if such a pathogenic role may be attributed to accessory cells in mycosis fungoides it is more probably exerted by dermal interdigitating cells and not by Langerhans cells, as previously proposed.     

Virus propagation, virus replication and virus elimination in the human skin in zoster]

The purpose of this study was to investigate the spreading, the replication and the elimination of Varicella-Zoster-Virus (ZV) in human skin. Typical skin lesions of thoracic zoster in different stages of development and of exanthematic vesicles in ophthalmic zoster were examined under the electron microscope. We found that ZV may be detected in fully developed vesicular skin lesions only, whereas in immature lesions and in the surrounding non involved skin axonal alterations may be seen, with no ZV present. The replication of the virus in the skin takes place almost exclusively in the malpighian keratinocytes of the involved epidermis. Blister formation in zoster is basically a result of the acantholysis of the infected epidermal cells. Mature ZV are then extruded into the intercellar space and become phagocytised by mononuclear cells which infiltrate the epidermis and eliminate the virus in large phagolysosomes. Only few virions were found in the dermis extracellularly or in dermal macrophages. In some of these cells stages of ZV-replication were also seen. Other cell types (i.e. Langerhans cells) were rarely infected. The application of the periodic acid-silver methenamine technique (PASM) in zoster revealed that a glycoprotein-rich coat surrounds each mature virion, obviously originating from the plasma membrane of the infected keratinocytes. This coat may be reason for the ability of the ZV to adhere on the cell surface and to infect the cell.     

Iron chelation can modulate UVA-induced lipid peroxidation and ferritin expression in human reconstructed epidermis

BACKGROUND/PURPOSE: As ferritin has been identified as an important factor in antioxidant defense in cultured human skin cells, we evaluated UVA-induced lipid hydroperoxides (LPO) production and ferritin expression in reconstructed human epidermis in vitro. RESULTS: Ferritin is regularly present in the basal layer of unirradiated epidermis both in the human skin in vivo and in the reconstructed human epidermis in vitro. Following acute UVA exposure, ferritin expression increased in basal epidermal cells in both models. Quantitative analysis showed that, in reconstructed human epidermis, LPO and ferritin levels increased linearly with the UVA dose. An iron chelator, OR10141, inhibited these inductions. CONCLUSION: These findings demonstrate that reconstructed human epidermis is a useful in vitro model to study UVA-induced oxidative stress and protection afforded by iron chelators, antioxidants or UVA absorbers.